1. Field of the Invention
The present invention relates to a lens-fitted photo film unit with an optical adapter. More particularly, the present invention relates to a lens-fitted photo film unit with which an optical adapter is externally combined for the purpose of an exposure in a specific photographing mode.
2. Description Related to the Prior Art
A lens-fitted photo film unit is well-known as a single-use camera of a simple structure. JP-A 7-092552 and 2000-122233 disclose the lens-fitted photo film unit of a type capable of an exposure in a specific photographing mode of various types in which a standard photographing mode is modified. Examples of the specific photographing modes include the soft focus photography, the snow cross photography with a snow cross filter, and the slim photography in which a lateral size of an object is reduced or compressed, or a vertical size of the object is extended.
JP-A 10-307324 discloses the lens-fitted photo film unit in which an optical adapter includes a lens element, filter element or other optical element for the specific photographing mode, and secured to a front cover of a housing by use of a specialized connection belt. JP-A 2000-162690 discloses the lens-fitted photo film unit in which the optical adapter in a crank shape is combined, and includes a disk-shaped plate having plural optical systems for the purpose of the specific photographing mode. Furthermore, there are documents JP-A 8-015763, 11-038480, 11-352546 and 2002-090948 disclosing an optical adapter.
However, JP-A 10-307324 requires the use of connection belts for combining the optical adapter with the housing. This raises the manufacturing cost of relevant parts, and enlarges the size of the products. JP-A 2000-162690 discloses the optical adapter of which the vertical size is larger than that of the housing. So a size of the products will be enlarged inevitably.
JP-A 10-307324 and 2000-162690 do not disclose positioning of the optical adapter in a vertical or horizontal direction. It is likely that the quality of an image at the time of the specific photographing mode will be low due to the offsetting of the optical adapter. The optical adapter is pressed on the outside of a belt-shaped outer sheet covering the front cover. In relation to the optical axis direction of the taking lens, there is no correct positioning because of flexing of the belt-shaped outer sheet.
Furthermore, there is no suggestion in JP-A 7-092552, 2000-122233, 10-307324 and 2000-162690 of treating or compensating for a remarkable difference between the field of view in the viewfinder for framing the object and a region of actually photographing the object. This is a shortcoming typically involved with the specific photographing mode in which the lateral size of the object is compressed in a slim manner.
In view of the foregoing problems, an object of the present invention is to provide a lens-fitted photo film unit with which an optical adapter is externally combined for the purpose of an exposure in a specific photographing mode, and in which image quality can be high, and a structure can be simple.
In order to achieve the above and other objects and advantages of this invention, a lens-fitted photo film unit includes a main body pre-loaded with photo film. A taking lens is incorporated in the main body. A front cover covers a front of the main body, has a lens opening where the taking lens is disposed. An optical adapter is secured to the front cover and used for a specific photographing mode. The optical adapter includes an adapter optical element for passing object light to become incident on the taking lens. A movable support mechanism connects the adapter optical element with the front cover, wherein the movable support mechanism is shiftable between a standard position and a specific position, and when in the standard position, offsets the adapter optical element from the taking lens, and when in the specific position, sets the adapter optical element in front of the taking lens.
Furthermore, an optical element holder or holder frame has a holder opening for retaining the adapter optical element inside. The movable support mechanism connects the optical element holder with the front cover.
The adapter optical element includes a cylindrical lens for enlarging or compressing an object image in a predetermined direction.
Furthermore, an outer sheet is secured to a front face of the front cover. An opening is formed in a portion of the outer sheet for contact of the optical adapter with the front cover, for causing the optical adapter directly to contact the front cover.
In a preferred embodiment, furthermore, a viewfinder is incorporated in the main body, for observation of a photographic object through the front cover. The optical element holder includes a viewfinder field window, disposed in front of the viewfinder when in the specific position, for limiting a view field to a photographable region according to operation of the adapter optical element for the specific photographing mode.
Furthermore, an adapter body or retention panel is retained on the front cover removably. The movable support mechanism includes a pivotal shaft and a bearing portion for supporting the pivotal shaft in a rotatable manner, and the pivotal shaft and the bearing portion include one secured to the optical element holder, and a remaining one secured to the adapter body.
Furthermore, a stopper mechanism prevents the optical element holder in the standard position from moving beyond the standard position.
The stopper mechanism includes a first stopper projection, formed to project from the adapter body, and disposed close to the movable support mechanism. A second stopper projection is formed to project from the optical element holder, disposed close to the movable support mechanism, for engagement with the first stopper projection when the optical element holder is in the standard position, to prevent a downward swing beyond the standard position.
The predetermined direction is vertical, the standard position is disposed lower than the specific position, and the optical element holder when in the standard position is positioned lower than an angle of view defined by the taking lens.
Furthermore, at least one central projection portion is formed to project from the front cover about the lens opening. A receiving opening is formed in the adapter body behind the adapter optical element, for being fitted on the central projection portion, or for receiving the central projection portion.
Furthermore, a first engaging portion is formed with the adapter body. A second engaging portion is formed with the optical element holder, engaged with the first engaging portion, for retaining the optical element holder on the adapter body removably when the optical element holder is in the specific position.
Furthermore, a connection recess is formed in the front cover. A connection projection is formed to project from a rear face of the adapter body, fitted in the connection recess, for securing the adapter body to the front cover.
Furthermore, a cutout is formed in a peripheral edge of the adapter body, positioned in association with the connection projection, for keeping observable at least one portion of the connection projection.
Furthermore, a pressing projection is formed to project from one of a rear face of the optical element holder and a front face of the adapter body, for pressing a remaining one of the rear face of the optical element holder and the front face of the adapter body, to transmit pressing force of the optical element holder to the adapter body in securing to the front cover, whereby pressure for engagement is applied to the connection projection toward the front cover.
The pressing projection projects from the rear face of the optical element holder, and presses the front face of the adapter body.
The optical element holder includes a front wall having the holder opening. First and second lateral panels are formed to project from first and second lateral edges of the front wall to a rear. The pressing projection is constituted by two pressing projections, formed on a rear face of the front wall, and disposed close to the first and second lateral panels.
The front wall is curved in an arc shape convex to a front.
The movable support mechanism has a rotational axis extending along one edge of the optical element holder and the adapter body.
The one edge is a lower edge, and the bearing portion is a bearing hook.
Furthermore, a positioning hole is formed in the front cover. A positioning boss is formed to project from a rear face of the adapter body, inserted in the positioning hole for positioning.
Furthermore, a pressing projection is formed to project from an inner edge of the holder opening, for tightening a contact with a peripheral edge of the adapter optical element.
Furthermore, a retention claw is formed to project from an inner edge of the holder opening, for retaining a peripheral edge of the adapter optical element.
According to one aspect of the invention, there is provided an optical adapter for a lens-fitted photo film unit pre-loaded with photo film, and having a taking lens, and a front cover including a lens opening where the taking lens is disposed. The optical adapter comprises an adapter body or retention panel. An engaging portion secures the adapter body to the front cover. An optical element holder or holder frame has a holder opening, and is secured to the adapter body movably. An adapter optical element is retained in the holder opening, for passing object light incident thereon when set in front of the taking lens. A pressing projection is formed to project from one of a rear face of the optical element holder and a front face of the adapter body, for pressing a remaining one of the rear face of the optical element holder and the front face of the adapter body, to transmit pressing force of the optical element holder to the adapter body in securing to the lens-fitted photo film unit, whereby pressure for engagement is applied to the engaging portion toward the front cover.
According to another aspect of the invention, there is provided an optical adapter for a lens-fitted photo film unit having a taking lens, and a front cover including a lens opening where the taking lens is disposed. The optical adapter comprises an adapter optical element for being set in front of the taking lens, for passing object light incident thereon. An adapter body or retention panel is secured to the front cover behind the adapter optical element. An optical element holder or holder frame is secured to the adapter body in a removable manner, has a holder opening for retaining the adapter optical element inside.
The optical element holder is usable in place of a first optical element holder on the adapter body. The first optical element holder retains a first adapter optical element inside, the first adapter optical element is set in front of the taking lens, for passing object light incident thereon.
The adapter optical element and the first adapter optical element are at least two of a cylindrical lens, a soft focus filter, and a close-up converter lens.
Furthermore, a movable support mechanism connects the optical element holder with the adapter body in a removable manner, wherein the movable support mechanism is shiftable between a standard position and a specific position, and when in the standard position, offsets the adapter optical element from the taking lens, and when in the specific position, sets the adapter optical element in front of the taking lens.
The movable support mechanism includes a pivotal shaft and a bearing portion for supporting the pivotal shaft in a rotatable manner, and the pivotal shaft and the bearing portion include one secured to the optical element holder, and a remaining one secured to the adapter body.
The pivotal shaft contacts the bearing portion at a first engaging amount equal to or smaller than a half of a width of the bearing portion.
In a preferred embodiment, the pivotal shaft has a greater length than a width of the bearing portion.
Furthermore, a stopper mechanism prevents the optical element holder in the standard position from moving beyond the standard position.
According to still another aspect of the invention, there is provided an optical adapter for a camera including a taking lens and a front cover having a lens opening where the taking lens is disposed. An adapter optical element is set in front of the taking lens, for passing object light incident thereon. An optical element holder or holder frame is secured to the front cover in a removable manner, having a holder opening for retaining the adapter optical element inside.